Tenebrio molitor larvae represent a sustainable protein source for food and feed. The aim of this study was to evaluate the supplementation of chestnut shell, a by-product of the agro-industrial chain, in growth substrates for T. molitor larvae rearing. Seven-week-old larvae were reared on three different growth substrates: the control group (CTRL) was fed wheat bran, treatment group one was fed wheat bran supplemented with 12.5% w/w chestnut shell (TRT1), and treatment group two was fed wheat bran supplemented with 25% w/w chestnut shell (TRT2). Larval weight, substrate consumption, and mortality were recorded weekly. After 14 days, insect meals were produced for bromatological and colorimetric analysis, and bacterial inhibition activity assay using a microdilution method. The amino acid profile of insects was determined using quantitative nuclear magnetic resonance spectroscopy. Our results showed a lower feed conversion ratio and higher larval survival rate % in TRT2 compared to CTRL (p < 0.05). Proteins and lipids of TRT2 were higher than other groups (p < 0.05). Important differences were observed in the amino acid profile of TRT1 and TRT2 compared to CTRL (p < 0.05). TRT1 and TRT2 showed higher E. coli inhibitory activity than CTRL (p < 0.05). In conclusion, chestnut shell supplementation improved the survival and functional characteristics of larvae and likely impacted the insects’ metabolism.

Background: Agro-industrial by-products, such as carob and brewer’s spent grain (BSG), have gained increasing attention as sustainable feed ingredients capable of enhancing the nutritional and functional value of Tenebrio molitor larvae. This study aimed to evaluate the effects of carob and BSG supplementation of growth substrates on larval performance and the functional properties of the resulting insect meals. Methods: Seven-week-old larvae were reared for 14 days on the following three diets: control (wheat bran), wheat bran + carob (Trt1), and wheat bran + BSG (Trt2). Larval weight, substrate consumption, and survival were recorded. After processing, insect meals were analyzed for chemical composition, total phenolic content (TPC), and antioxidant activity in both water- and lipid-soluble extracted fractions. Results: Both treatment groups showed significantly higher final weights than the control (Ctrl: 104.9 ± 2.69 g; Trt1: 114.8 ± 1.26 g; Trt2: 116.9 ± 1.07 g; p < 0.05). TPC was highest in the control for both fractions, and the antioxidant activity was similar between the Ctrl and Trt1 groups in the water-soluble fraction but significantly lower in the Trt2 group (p < 0.05). Conclusions: These findings highlight the potential of carob and BSG for sustainable insect farming, though their functional benefits may depend on the inclusion levels and their interaction with insect metabolism.

Taurine plays a key role in cardiovascular and gastrointestinal health in dogs and may be deficient in some predisposed breeds despite consuming complete petfood. This study aimed to explore potential associations between serum taurine concentration and gut microbiota composition in clinically healthy Golden Retrievers, a breed predisposed to taurine deficiency-associated dilated cardiomyopathy. Eleven adult dogs, which were fed the same extruded commercial diet and living in the same kennel, underwent a nutritional evaluation, fecal analysis, and measurement of serum concentrations of taurine, folates, and vitamin B12. Taurine levels were below reference values in eight out of eleven dogs, and 50% of the tested dogs showed reduced serum folate. Microbiota analysis based on 16S rRNA sequencing revealed subtle compositional shifts in dogs with lower taurine levels, including a depletion of mucus-associated Deferribacterota and an enrichment of bile-sensitive taxa such as Lactobacillus and Streptococcus. While alpha and beta diversity metrics did not differ significantly between groups, unweighted UniFrac indicated a trend toward separation. These findings suggest that hypotaurinemia in Golden Retrievers may be associated with specific alterations in the gut microbiota, potentially reflecting subclinical dysbiosis. Further studies integrating metabolomic profiling are needed to clarify the functional implications of these microbial changes on taurine metabolism.

Coprophagy is a common behavior in domestic dogs, yet its effects on the intestinal microbiota and asymptomatic carriage of enteropathogens remain unclear. This study aimed to determine whether healthy coprophagic dogs differ from non-coprophagic dogs in fecal microbiota composition or prevalence of asymptomatic enteropathogen carriage. Forty-four clinically healthy dogs were prospectively enrolled, including 23 coprophagic and 21 non-coprophagic animals as reported by their owners. Ages spanned from 6 to 119 months old, including 19 mixed-breed dogs and 25 purebred dogs, and diet was not controlled for. Fecal samples were analyzed using quantitative PCR to determine the canine dysbiosis index, quantify core bacterial taxa, and detect selected enteropathogens, including Clostridium perfringens, Clostridioides difficile, Campylobacter jejuni, Salmonella spp., canine parvovirus, and toxin-associated genes. Demographic and microbiological data were compared between groups, with correction for multiple testing. No significant differences were observed between coprophagic and non-coprophagic dogs in dysbiosis index (q = 1), abundance of the core bacterial taxa evaluated (q = 0.17–1), or detection of enteropathogens (q = 0.734–1) after adjustment for multiple comparisons. Enteropathogens were absent or detected infrequently in both groups. These findings indicate that coprophagy in otherwise healthy dogs is not associated with measurable alterations in dysbiosis index, core fecal microbiota, or increased enteropathogen carriage.

The demand for sustainable protein sources for companion animal nutrition has stimulated interest in insect-derived ingredients. Tenebrio molitor larvae meal is a promising alternative to conventional proteins because of its nutritional composition and functional properties. This study evaluated the nutritional quality, in vitro digestibility, chitin digestibility, and antioxidant properties of T. molitor meal using canine- and feline-adapted in vitro digestion models. Chemical composition, amino acid and fatty acid profiles, total, protein, lipid, and chitin digestibility, antioxidant activity (ABTS), and Folin–Ciocalteu reducing capacity were determined. T. molitor meal contained 44.3% crude protein and 21.0% ether extract, with a balanced amino acid profile and a lipid fraction dominated by oleic and linoleic acids. Compared with the fish meal evaluated in this study, T. molitor showed higher total and lipid digestibility in both models, whereas protein digestibility was higher in dogs and comparable in cats. Chitin accounted for approximately 7.6% of the meal and showed negligible apparent digestibility. Water extracts of T. molitor exhibited greater antioxidant activity and reducing capacity than fish meal. These findings support the potential of T. molitor larvae meal as an alternative protein ingredient for companion animal nutrition, although in vivo studies are needed to confirm these observations.